docs: update style guidelines for documentation contributions

[agilgur5]

Motivation

Update documentation guidelines to reference the much more detailed upstream k8s guidelines

• Stumbled upon this for the first time in a long while, during recent PR reviews for the Developer tab of the docs

Modifications

• refer to the k8s style guide, which is pretty highly quality with good examples

  • and which I use often to guide my technical writing, including in many previous PRs to this repo
  • remove duplicative content that is already mentioned in the k8s style guide, such as "avoid jargon"
  • remove an example that contradicts the k8s style guide
    • it actually should be "the Workflow" as it is an API object: https://kubernetes.io/docs/contribute/style/style-guide/#use-upper-camel-case-for-api-objects

• remove incorrect title-case comment

  • "And" is in fact usually not capitalized by most title-case writing standards
    • Wikipedia style manual specifically excludes "short coordinating conjunctions" and specifically lists "and"
    • same with AMA style manual

• fix a missing comma and missing words here as well

  • e.g. "being reported spelling error" -> "being reported as a spelling error"
  • add a title to this bulleted list

Verification

make docs passes

[agilgur5]

Blarg, spell check is failing on "shortcodes" and "EditorConfig", which I thought I could avoid by literally quoting the words 😕

Could backtick instead, but these aren't code, so may have to add to .spelling despite them only being used as a reference and not in our own docs